877 as a Bridge?

[QCumber]

Hi there,

I know it's a waste of a fairly decent spec bit of kit, but it was lying in a box, gathering dust...

Can anyone please help me out with a simple bridge config for a Cisco 877? All I need it to do is pass my static public IP through to the Outside interface of the ASA5505 that sits behind it. I don't need any of the other 877 interfaces (especially the wireless) active.

I've just spent couple of hours googling various configs and am now more confused than ever. My (UK) ISP uses PPPoA, and I'm really not sure which interface needs to have the ppp chap sign-in details (vlan1 or dialer0).

I currently don't have a config worth posting, so if someone could help out, I'd be very grateful!

Cheers,

Q.

 

[burtsbees]

How are you doing this now? Why even use the 877?
So---no wireless, PPPoA config, and bridge it? It can't be bridged this way---PPPoA means that it must negotiate a connection to get an IP address on the outside interface, which means it will be public, which means it must have a private IP add on the inside interface. This means it must route. If you wanted it as an access point, this would make sense.
The command
no ip routing
essentially turns it into a bridge, but as I say, this won't work.
A dsl modem will do the exact same thing...

Burt

 

[QCumber]

Hi Burt,

thanks for the reply. At the moment I'm using a Cisco 837 with a routed config. We now need to setup multiple DMZs on an ASA5505, with an enhanced security licence, on the same line.

I was going to buy a cheap DSL modem, like a Netgear DMP111 to terminate the ADSL line, but was then offered the 877. I don't want to touch the config on the 837, as it's currently working. So I was hoping to simply get the 877 to act as a modem.

Maybe I should just buy the Netgear...?

The (none working) config looks like this, for what it's worth:

bridge irb
!
!
interface ATM0
no ip address
no ip redirects
no ip unreachables
no ip proxy-arp
no atm ilmi-keepalive
dsl operating-mode auto
!
interface ATM0.1 point-to-point
description ATM For Internet
no snmp trap link-status
pvc 0/38
encapsulation aal5mux ppp dialer
dialer pool-member 1
!
!
!
bridge-group 1
bridge-group 1 spanning-disabled

interface Vlan1
description Internal Network
no ip address
no ip redirects
no ip unreachables
no ip proxy-arp
ip virtual-reassembly
bridge-group 1
!
interface Dialer0
ip address 195.xxx.xxx.xxx 255.255.255.0
no ip redirects
no ip unreachables
no ip proxy-arp
ip nat outside
ip virtual-reassembly
encapsulation ppp
ip route-cache flow
load-interval 60
dialer pool 1
dialer idle-timeout 0
dialer wait-for-line-protocol 1
dialer wait-for-carrier-time 1
dialer persistent
dialer-group 1
no snmp trap link-status
no cdp enable
ppp authentication chap pap callin
ppp chap hostname xxxxxxxxxxxxxxxxxxxx
ppp chap password 7 xxxxxxxxxxxxxxxxxx
!
!
ip classless
ip route 0.0.0.0 0.0.0.0 Dialer0

 

[burtsbees]

So are they dirty dmz's (public IP addresses), or can you statically NAT them? If so, your 837 can be left alone---albeit the 877 can do self-vlans, but L2 only, really...is thios why you want to use the 877?

Burt

 

[QCumber]

Hi Burt,

I'm leaving the 837 in place to maintain the service to users until all the config & testing is complete.

The DMZs will be using NAT, although I believe there is a block of public IPs available on this service.

Someone else has suggested this as the config for the 877:

interface ATM0
pvc 0/38
encapsulation aal5snap
!
dsl operating-mode auto
bridge-group 1
!
interface Vlan1
bridge-group 1
!
bridge 1 protocol ieee
!

....and let the ASA handle the PPP stuff. No idea if it'll work, but I'll have a go at it as soon as I get chance.

Q.